A Moisture-Resistant Soft Actuator with Low Driving Voltages for Haptic Stimulations in Virtual Games

Abstract

Strong and robust stimulations to human skins with low driving voltages under high moisture working conditions are desirable for wearable haptic feedback applications. Here, a soft actuator based on the “air bubble” electret structure is developed to work in high-moisture environments and produce haptic sensations to human skin with low driving voltages. Experimentally, the water soaking and drying process has been conducted repeatedly for the first time and the 20th time to test the antimoisture ability of the actuator as it recovers its output force up 90 and 65% of the initial value, respectively. The threshold voltages for sensible haptic sensations for the fingertip and palm of volunteers have been characterized as 7 and 10 V, respectively. Furthermore, a demonstration example has been designed and conducted in a virtual boxing game to generate the designated haptic sensations according to the gaming conditions with an accuracy of 98% for more than 100 tests. As such, the design principle, performance characteristic, and demonstration example in this work could inspire various applications with improved reliability for wearable haptic devices.

A Flexible Self-Powered Noncontact Sensor with an Ultrawide Sensing Range for Human–Machine Interactions in Harsh Environments

“…The inner positive charges help to recapture the negative charges even when the outer surface of the electret contacts water, thus enhancing the robustness in harsh environments. 44,45 When soaked in water, the major negative charges of the ENSs with these two structures are neutralized by water because of physical contact, resulting in the decrease in surface potential of the ENS. Surprisingly, the ENS with an air-bubble structure exhibits a gradual recovery of surface potential after being taken out of water (Video S1).…”

“…For the ENS with an air-bubble structure, the FEP film traps negative and positive charges on its two sides separately after negative corona charging. , The induced positive charges form a strong electrostatic force with negative charges, which prevents both charges from escaping. The inner positive charges help to recapture the negative charges even when the outer surface of the electret contacts water, thus enhancing the robustness in harsh environments. , When soaked in water, the major negative charges of the ENSs with these two structures are neutralized by water because of physical contact, resulting in the decrease in surface potential of the ENS. Surprisingly, the ENS with an air-bubble structure exhibits a gradual recovery of surface potential after being taken out of water (Video S1).…”

Soft Sensors and Actuators for Wearable Human–Machine Interfaces

“…(c) Piezoelectret actuator. Reproduced with permission from ref . Copyright 2022 American Chemical Society.…”

Hydraulically Amplified Electrostatic Taxels (HAXELs) for Full Body Haptics

“…[8,34] Electret-based soft actuators have been reported on fingers. [35] There have been several approaches to make wearable haptics mechanically invisible, including on-skin tattoos based on electrostimulation [36] and 20 μm thick DEA on fingertips. [32] With such devices, the user feels only the actuator's mechanical feedback but neither the weight nor any mechanical hindrance from the actuator.…”